Field of the Invention. The standard metal cake pan has its bottom and side walls made from a single metal sheet. During the baking of the cake, the oven heat will cause the side walls of the pan to become heated sufficiently to melt the exposed grease or shortening on the inner surfaces of the side walls that lie above the sides of the batter that contacts the pan with the result that the sides of the batter will be browned prematurely and the batter sides cannot rise uniformly with the central portion of the batter during the baking of the cake. The result will be that the central portion of the cake batter will rise more than the sides and this will give a crown effect to the baked cake. If a multilayered cake is being made, the crown portion of the cake must be cut off so as to evenly support the flat undersurface of the next higher layer.
A further difficulty arises from the fact that the side walls of the cake pan were heated by the oven heat before the cake batter had completed rising and this caused the premature melting of the shortening on the inner side of the pan resulting in a non-lubrication of the side walls and a hindering of the ready rising of the cake batter that contacted the non-lubricated and heated side walls.
The present invention discloses an outer and an inner pan and the space between the side walls of the inner and outer pans is filled with water which functions as a heat insulation for the inner wall. The novel locking means that secures the two pans together also holds the inner pan in a position where its bottom wall contacts the bottom wall of the outer pan and prevents any water coming between these two bottom walls. The result is that in the baking of a cake, the bottom wall of the inner pan will be heated to a greater extent than the side walls of the inner pan because these side walls are insulated from the oven heat due to their being surrounded by a layer of water that functions as an insulating medium for the inner wall.
It should be understood that although the drawings show both the inner and outer pans as being rectangular in shape, my invention is well adapted to be used in inner and outer pans that have circular side walls.